"(I'm feeling) a lot better," Brown said. "Working towards 100 percent. It's been a process with the feet. Any time you got a lot of blisters, it's hard to change direction, cut and run and be able to do what I do naturally."

Coach Jon Gruden said he isn't sure if Brown will suit up for Oakland in the preseason, but he expects Brown to be ready by Week 1.

When asked when he'll return to practice, Brown told reporters to "stay tuned."

Kirby Lee-USA TODAY Sports(Photo: Kirby Lee-USA TODAY Sports)

Brown also said he is working with the NFL to find an approved helmet to wear for the upcoming season after an arbitrator rejected his grievance against the NFL on Monday. The 31-year-old wide receiver, who was traded to Oakland during the offseason, has wanted to wear his old helmet even though it has not been certified for use in 2019. (The National Operating Commission on Standards for Athletic Equipment does not certify helmet models that are more than 10 years old.)

"They have to certify it and do all the procedures," Brown said Tuesday, when asked about his helmet search. "But we're working with the NFL to make sure we're following all the procedures to be out there in the right equipment."

NFL Network reported Friday that Brown grew frustrated with the Raiders when they repeatedly tried to push him to wear a newer, approved helmet model, even going so far as trying to paint his old helmet and sneak it onto the practice field.

In his latest attempt to find suitable headgear, Brown put out a tweet Tuesday morning offering to trade a signed helmet to a fan in exchange for "a Schutt Air Advantage Adult Large Helmet that was manufactured in 2010 or after."

Browns' agent, Drew Rosenhaus, told the Las Vegas Review-Journal that his team had "located helmets that have been manufactured within the past 10 years" and were working to get them cleared.

General overall view as Dallas Cowboys quarterback Dak Prescott (4) hands the ball off to running back Tony Pollard (36) in the first quarter against the Los Angeles Rams at Aloha Stadium in Honolulu, Hawaii. Kirby Lee, USA TODAY Sports

Jacksonville Jaguars defensive end Datone Jones (96) hits Philadelphia Eagles quarterback Cody Kessler (2) during the first quarter at TIAA Bank Field. Kessler would have to leave the game after the play. Reinhold Matay, USA TODAY Sports

New York Giants quarterback Daniel Jones (8) celebrates after throwing a touchdowns pass with defensive tackle Dexter Lawrence (97) and offensive guard Will Hernandez (71) during the first half against the New York Jets at MetLife Stadium. Vincent Carchietta, USA TODAY Sports

New York Jets wide receiver Jamison Crowder (82) celebrates after a touchdown reception with offensive guard Kelechi Osemele (70) during the first half against the New York Giants at MetLife Stadium. Vincent Carchietta, USA TODAY Sports

Jacksonville Jaguars tight end James O'Shaughnessy (80) works out with teammates prior to an NFL football preseason game against the Baltimore Ravens, Thursday, Aug. 8, 2019, in Baltimore. Julio Cortez, AP